Vehicle control apparatus

ABSTRACT

A vehicle control apparatus is mounted on a vehicle to perform wireless communication with a portable terminal. The vehicle control apparatus includes a first processor configured to execute a first process including a determination process that determines whether or not a received signal, which is a wireless signal received by an antenna mounted on the vehicle and encoded, is a regular wireless signal transmitted from the portable terminal by determining whether or not a counted number of short bits sandwiched by two long bits adjacent to each other in the received signal is an even number.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of Internationalpatent Application No. PCT/JP2019/036605 filed on Sep. 18, 2019, whichdesignated the U.S. and claims the benefit of priority from JapanesePatent Application No. 2018-178674 filed on Sep. 25, 2018. The entiredisclosures of all of the above applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to a vehicle control apparatus.

BACKGROUND

Vehicle control apparatuses mounted on vehicles may include a vehiclecontrol apparatus that wirelessly communicates with a portable terminalcarried by a user of the vehicle to realize a smart entry function or aremote keyless entry function. The smart entry function means a functionof unlocking the door of the vehicle when the portable terminal enters awireless communication area near the vehicle. Further, the remotekeyless entry means a function of locking or unlocking the door of thevehicle according to the operation of the push switch of the portableterminal. Generally, such a vehicle control apparatus, which may also becalled an in-vehicle apparatus, can receive a signal in an RF band (forexample, 300 MHz to 400 MHz) transmitted from a portable terminal, andcan transmit a signal in an LF band (for example, 30 kHz to 300 kHz) tothe portable terminal.

SUMMARY

According to an aspect of the present disclosure, a vehicle controlapparatus is mounted on a vehicle to perform wireless communication witha portable terminal. The vehicle control apparatus includes a firstprocessor configured to execute a first process including adetermination process that determines whether or not a received signal,which is a wireless signal received by an antenna mounted on the vehicleand encoded, is a regular wireless signal transmitted from the portableterminal by determining whether or not a counted number of short bitssandwiched by two long bits adjacent to each other in the receivedsignal is an even number.

BRIEF DESCRIPTION OF DRAWINGS

The objects, features, and advantages of the present disclosure willbecome more apparent from the following detailed description made withreference to the accompanying drawings. In the drawings:

FIG. 1 is a block diagram showing schematic configurations of (i) avehicle equipped with a vehicle control apparatus as a first embodimentof the present disclosure and (ii) a vehicle system including thevehicle control apparatus;

FIG. 2 is a block diagram showing a vehicle system according to thefirst embodiment;

FIG. 3 is a flowchart showing steps of an RF signal reception handlingprocess of the first embodiment;

FIG. 4 is a flowchart showing steps of a determination process for aregular wireless signal;

FIG. 5 is an explanatory diagram showing an example of encoding with abi-phase FSK system;

FIG. 6 is a block diagram showing a detailed configuration of a vehiclesystem according to a second embodiment;

FIG. 7 is a flowchart showing steps of a RF signal reception handlingprocess according to the second embodiment; and

FIG. 8 is a flowchart showing steps of a second determination processfor a regular wireless signal according to the second embodiment.

DETAILED DESCRIPTION A. First Embodiment

A1. Apparatus Configuration

As shown in FIG. 1, a vehicle control apparatus 10 according to a firstembodiment is used by being mounted on a vehicle 100 as a part of avehicle system 500. The vehicle system 500 implements remote keylessentry. The remote keyless entry means that when the user of the vehicle100 operates a push switch (not shown) of a portable terminal 200, thedoor of the vehicle 100 is opened, closed, unlocked, locked, etc.according to the operation. A smart entry may be realized instead of theremote keyless entry or in addition to the remote keyless entry. Thesmart entry means (i) that the door of the vehicle 100 is unlocked whenthe user of the vehicle 100 carrying the portable terminal 200 enters awireless communication area near the vehicle 100, and (ii) that thevehicle 100 is started by the user sitting in the driver's seat whilecarrying the portable terminal 200 and operating a predetermined switch.The vehicle control apparatus 10 is also called an in-vehicle apparatus.

The vehicle system 500 includes the vehicle control apparatus 10 and theportable terminal 200, which can wirelessly communicate with each other.The portable terminal 200 is used by being carried by a user as anelectronic key for the vehicle 100. The portable terminal 200 includes,in addition to the push switch not shown, (i) a configuration fortransmitting a signal in the RF band (for example, 300 MHz to 400 MHz)(hereinafter referred to as “RF signal”), and (ii) a configuration forreceiving a signal in the LF band (30 kHz to 300 kHz) (hereinafterreferred to as “LF signal”). The configuration for transmitting the RFsignal may include an antenna, an amplification circuit, a modulationcircuit, and a control IC (Integrated Circuit).

In the present embodiment, the portable terminal 200 and the vehiclecontrol apparatus 10 adopt a bi-phase FSK (Frequency Shift Keying)system (i.e., type) as a modulation and encoding process in RF bandwireless communication. As shown in FIG. 5, in an encoding process inthe bi-phase FSK system (i.e., bi-phase FSK encoding process), the data“1” is represented by the entire code 1-bit cycle with either H (High)or L (Low), and the data “0” is represented by switching between L and Hat half cycle that is almost half the code 1 bit cycle (hereinafterreferred to as “half bit cycle”). In FIG. 5, in order to facilitateunderstanding, times t1 to t11 for each half bit cycle are showntogether with the encoded signals. For example, from time t2 to t4, theencoded signal represents data “1”. From time t4 to t6, the encodedsignal represents data “0”. In this way, in bi-phase FSK encodingprocess, L or H that switches at a half-bit cycle is defined as a shortbit; L or H that switches in the code 1 bit cycle is defined as a longbit. That is, in bi-phase FSK encoding process, two consecutive shortbits represent “0” and a single long bit represents “1”. In the bi-phaseFSK encoding process, in order to clarify the boundary of each bitclear, when the data “1s” are consecutive, H and L are switched betweenthe long bit of the preceding “1” and the long bit of the following “1”.When the data “0s” are consecutive, H and L are switched between theshort bit in the latter half of the previous “0” and the short bit inthe first half of the subsequent “0”. In a modulation process in thebi-phase FSK system (i.e., bi-phase FSK modulation process), thefrequency of a digital signal as shown in FIG. 5 is switched betweenlong bits and short bits, and the digital signal is output as an analogsignal. In other words, it can be said that the bi-phase FSK modulationprocess is a modulation process corresponding to the bi-phase FSKencoding process. The control IC for transmitting the RF signal of theportable terminal 200 performs the encryption process on the data to betransmitted.

The configuration for receiving the LF signal described above includesan antenna, an amplifier circuit, an encoding circuit, and a control IC.

As shown in FIG. 2, the vehicle control apparatus 10 is configured by anECU (Electronic Control Unit) that includes an ASIC (ApplicationSpecific Integrated Circuit) 11, a CPU (Central Processing Unit) 12, amemory 13, and a CAN (Controller Area Network) communication unit 14.

The vehicle control apparatus 10 is connected to the RF receiver unit 20and the LF transmitter unit 30, and performs wireless communication inthe RF band and the LF band with the portable terminal 200.

The RF receiver unit 20 includes an RF antenna 21 and an RF receivercircuit 22. The RF receiver circuit 22 amplifies and encodes the RFsignal received by the RF antenna 21, and outputs it as a digitalsignal. The encoding process by the RF receiver circuit 22 is performedwith the above-mentioned bi-phase FSK system.

The LF transmitter unit 30 includes a plurality of LF antennas 31 and anLF transmitter circuit 32. As shown in FIG. 1, the LF antennas 31 areinstalled respectively at a plurality of positions in the vehicle 100.Specifically, they are installed in the driver's seat door, thepassenger seat door, the left and right doors in the rear seat, and therear gate, individually, as well as in the passenger compartment. The LFtransmitter circuit 32 modulates and amplifies the digital signal outputfrom the vehicle control apparatus 10, and transmits LF band electricwaves via the LF antennas 31.

The vehicle control apparatus 10 is also connected to the CAN 50 andcommunicates with other ECUs connected to the CAN 50. FIG. 1 and FIG. 2exemplify a body ECU 61 and an engine ECU 62 as other ECUs. The body ECU61 controls the unlocking and locking of the door of the vehicle 100,the lighting state of various lamps such as a hazard lamp, and the like.The engine ECU 62 controls driving of the engine of the vehicle 100.

The ASIC 11 functions as a first processor 111. The first processor 111executes a first process in RF signal reception handling process.Details of the RF signal reception handling process and the firstprocess will be described later.

The CPU 12 functions as a second processor 121 and the LF signaltransmission controller 122 by executing the control program stored inthe memory 13 in advance. The second processor 121 executes a secondprocess in the RF signal reception handling process described later.Details of the second process will be described later. The LF signaltransmission controller 122 controls the transmission of the LF signal.Specifically, the transmission timing of the LF signal, the transmissionperiod, generation of transmission data, and the like are performed.

The memory 13 includes a ROM (Read Only Memory) and a RAM (Random AccessMemory). The control program described above is stored in the ROM. Avehicle-related information storage 131 is provided in the ROM.Vehicle-related information is stored in the vehicle-related informationstorage 131 in advance. The vehicle-related information is informationrelated to the vehicle 100, and in the present embodiment, includes theidentifier that can distinguish the vehicle 100 from other vehicles. Inaddition to such an identifier, the vehicle-related information includesany other information about the vehicle, such as information indicatinga vehicle manufacturer, information indicating an engine model number,and information indicating an identifier capable of discriminating auser.

The CAN communication unit 14 controls communication via the CAN 50. Asa result, the vehicle control apparatus 10 can exchange data with otherECUs. For example, the body ECU 61 can be instructed to blink the hazardlamp.

The vehicle control apparatus 10, the RF receiver unit 20, the LFtransmitter unit 30, the body ECU 61, and the engine ECU 62 describedabove are each supplied with power from a battery 70 mounted on thevehicle 100. Among these, the vehicle control apparatus 10, the RFreceiver unit 20, and the LF transmitter unit 30 are supplied with powerfrom the battery 70 even while the vehicle 100 is parked. As a result,the vehicle control apparatus 10 can receive the RF signal and transmitthe LF signal even while the vehicle 100 is parked. In the presentembodiment, the operation mode of the CPU 12 is selectively switched toeither the sleep mode or the normal mode. The sleep mode is an operationmode in which only a very small amount of processing such as switchingof operation modes can be executed, and the power consumption is verylow. On the other hand, the normal mode is an operation mode in whichall the processes executable by the CPU 12 can be executed, and thepower consumption is higher than that in the sleep mode. While thevehicle 100 is being parked, the operation mode of the CPU 12 is a sleepmode.

The vehicle control apparatus 10 having the above-describedconfiguration executes an RF signal reception handling process describedlater. The RF signal reception handling process includes (i)determination of whether the received RF signal is a wireless signaltransmitted from a portable terminal (hereinafter referred to as“regular wireless signal”); (ii) authentication of whether the receivedRF signal is a wireless signal transmitted from the portable terminal200 which is a portable terminal for the vehicle 100; and (iii)processing for realizing the process according to the control contentindicated by the wireless signal when authentication is successful. Theabove RF reception handling process is executed by the vehicle controlapparatus 10. This can reduce the power consumption of the vehiclecontrol apparatus 10 when receiving external noises in the RF banddifferent from the regular wireless signal. This can prevent the batteryexhaustion from occurring.

A2. RF Signal Reception Handling Process

The RF signal reception handling process shown in FIG. 3 is started whenthe vehicle 100 is shifted to a parking state. The parking state means astate in which the door of the vehicle 100 is being locked after theignition of the vehicle 100 is switched from ON to OFF and the userholding the portable terminal 200 leaves the vehicle 100. The fact thatthe user left the vehicle 100 with the portable terminal 200 can bedetermined, for example, by transmitting LF signals from all the LFantennas 31 and not receiving RF signals within a predetermined timeafter transmitting.

The first processor 111 determines whether an RF signal is received viathe RF receiver unit 20 (step S110). When it is determined that the RFsignal is not received (step S110: NO), step S110 is executed again.That is, the first processor 111 waits until it receives the RF signal.The case of receiving the RF signal corresponds to (i) the case wherethe user holds the portable terminal 200, approaches the vehicle 100,presses the push button of the portable terminal 200, or (ii) the casewhere external noise in the RF band is received. Such external noiseincludes (i) a signal transmitted from portable terminals for othervehicle control apparatuses; (ii) a signal of wireless communicationbetween a device installed in each parking space in a parking lot and amanagement apparatus for managing the parking lot; (iii) wireless wavesoutput from various towers; and (iv) electromagnetic waves output fromfluorescent lamps or broken neon signs.

When it is determined that the RF signal is received (step S110: YES),the first processor 111 executes a regular wireless signal determinationprocess (step S115). Based on the result of the regular wireless signaldetermination process, it is determined whether the received RF signalis a regular wireless signal (step S120). In the present embodiment,steps S115 and S120 correspond to a first process and a determinationprocess in the present disclosure.

As shown in FIG. 4, in the regular wireless signal determinationprocess, the first processor 111 determines whether the time lengths ofthe short bit and the long bit sampled from the received RF signal areboth within a predetermined time range (step S205). The sampled shortbits and long bits may be all the short bits and long bits receivedwithin a predetermined time from the start of receiving the RF signal.Further, the sampled short bits and long bits may be a predeterminednumber of short bits and long bits received at optional timing. As shownin FIG. 5, a regular wireless signal is adjusted and output so that thelong bit time length TL and the short bit time length TS are each withina predetermined time range. For example, the long bit time length TL maybe 0.7 microseconds and the short bit time length TS may be 0.35microseconds. On the other hand, in the case of external noise, the timelength of the long bit or the short bit may deviate from such apredetermined time range. Further, even for a regular wireless signal,the time length of the long bit or the short bit may deviate from thepredetermined time range depending on the surrounding communicationenvironment such as the size and type of the interception. In thepresent embodiment, the predetermined time range is set as a limit valuethat is a value obtained by increasing or decreasing the design value ofthe time length of each of the long bit and the short bit by apredetermined ratio. In the present embodiment, the predetermined ratiois 30%. It is assumed that various interceptions exist between thevehicle 100 and the portable terminal 200. Therefore, the time lengthsof the long bit and the short bit may deviate significantly from thedesign values even in a regular wireless signal. Therefore, in order tocorrectly determine that the signal is a regular wireless signal, arelatively large value of 30% is set as the predetermined ratio. Theabove-mentioned predetermined ratio is not limited to 30% and may be anyratio of 0% or more.

When it is determined that the time lengths of the short bit and thelong bit are both within the predetermined time range (step S205: YES),it is determined whether the number (i.e., a counted number) of shortbits sandwiched between two adjacent long bits is an even number (stepS210). In the signal obtained by the bi-phase FSK encoding process, thenumber of short bits sandwiched between two adjacent long bits is aneven number. For example, as shown in FIG. 5, the short bits sandwichedbetween the long bit “1” from time t2 to t4 and the long bit “1” fromtime t8 to t10 is four from (a) to (d). Since the regular wirelesssignal is modulated by the bi-phase FSK system, the number of short bitssandwiched between two adjacent long bits in the digital signal obtainedby encoding is an even number. On the other hand, external noise is nottypically modulated by the bi-phase FSK system. Therefore, in thedigital signal obtained by encoding such a signal, in many cases, twotypes of bits (i.e., a long bit and a short bit) are not present, or thenumber of short bits sandwiched between two adjacent long bits is an oddnumber. However, it is still possible that the external noise happens tohave long bits and short bits, and the number of short bits sandwichedbetween two adjacent long bits may be an even number. In the presentembodiment, the determination in step S210 is performed for all the twolong bits adjacent to each other existing within the range of 9 bits intotal. In other words, it is determined whether the number of short bitssandwiched by each pair of all the pairs of two adjacent long bitswithin a total of 9 bits is an even number (step S210). The 9 bits heremean 9 cycles of bits when counted in a code 1 bit cycle. Note that stepS210 may be performed not only for 9 bits but for all adjacent long bitsexisting within an optional range of an optional number of bits otherthan 9 bits (i.e., within an optional bit width including an optionalnumber of bits other than 9 bits).

As illustrated in FIG. 4, when it is determined that the number of shortbits sandwiched between two long bits adjacent to each other is an evennumber (step S210: YES), the first processor 111 determines whether thedetermination bit exists within a predetermined bit width including apredetermined number of bits (step S215). The RF signal transmitted fromthe portable terminal 200 includes a determination bit for eachpredetermined bit width including a predetermined number of bits. Thedetermination bit is a bit set to specify that the RF signal is an RFsignal output from the portable terminal, and is set for eachpredetermined bit width including a predetermined number of bits. Notethat, if the RF signal transmitted from the portable terminal 200includes a determination bit for each predetermined first bit widthincluding a predetermined first number of bits, the first processor 111may determine in step S215 whether the determination bit exists within apredetermined second bit width including a predetermined second numberof bits that is equal to or larger than the first number of bitsincluded in the first bit width.

In this embodiment, a predetermined number of consecutive “1”s are usedas set determination bits. The predetermined number is 5, but it is notlimited to 5 and may be any number of 2 or more. Further, in the presentembodiment, the predetermined bit width includes 64 bits (64 cycles) inthe code 1 bit cycle, but it is not limited to 64 bits and may be anybit width including any number of bits larger than a predeterminednumber of consecutive “1 s”.

When it is determined that the set determination bits exist within thepredetermined bit width (step S215: YES), the first processor 111determines that the received RF signal is a regular wireless signal(step S220).

On the other hand, the first processor 111 determines that the receivedRF signal is not a regular wireless signal (step S225) in the followingscases: when it is determined in the above step S205 that at least one of(i) the time length of the short bit and (ii) the time length of thelong bit is not within the predetermined time range (step S205: NO);when it is determined in step S210 described above that the number ofshort bits sandwiched between two adjacent long bits is not an evennumber (step S210: NO); or when it is determined in step S215 describedabove that the set determination bits do not exist within thepredetermined bit width (step S220: NO). After step S225 and step S220,step S120 described above shown in FIG. 3 is executed.

The above step S205 corresponds to a second sub determination process inthe present disclosure. Further, step S210 corresponds to a first subdetermination process of the present disclosure. Step S215 correspondsto a third sub determination process of the present disclosure.

As shown in FIG. 3, when it is determined in step S120 that the receivedRF signal is not a regular wireless signal (step S120: NO), the processreturns to step S110. On the other hand, when it is determined that thereceived RF signal is a regular wireless signal (step S120: YES), themode switching function unit (not shown) of the CPU 12 switches theoperation mode of the CPU 12 from the sleep mode to the normal mode(step S125). When the CPU 12 switches to the normal mode, the vehiclecontrol apparatus 10 starts regular communication with the other ECUs61, 62 and the like via the CAN 50. As a result, the power consumptionof the CPU 12 sharply increases and the power consumption of the otherECUs 61, 62, etc. sharply increases, so that the power consumption ofthe vehicle 100 as a whole sharply increases.

After the execution of step S125, the second processor 121 executes asecond process. As described later, the second process includes aprocess including authentication (step S135 described later) of whetherthe portable terminal that is the transmission source of the received RFsignal is the portable terminal 200 for the vehicle 100. The powerconsumption of the CPU 12 when executing such authentication is high.Therefore, the total power consumption of the vehicle control apparatus10 by the second process is larger than the total power consumption ofthe vehicle control apparatus 10 by the first process described above.In the above-described first process, when it is determined that thereceived signal is not a regular wireless signal (step S120: NO), thesecond process is not executed and the process returns to step S110.Therefore, the power consumption of the battery 70 can be suppressed ascompared with the configuration in which the second process is executedwhen a signal that is not a regular wireless signal is received.

In the second process, first, the second processor 121 decrypts thereceived data (step S130). The second processor 121 executes anauthentication process based on the decrypted received data (step S135).In the present embodiment, the vehicle-related information included inthe received RF signal is compared with the vehicle-related informationstored in the vehicle-related information storage 131. When both match,it is determined that the authentication is successful (i.e., hassucceeded). When both do not match, it is determined that theauthentication is unsuccessful (i.e., has failed). Note that thevehicle-related information included in the received data may notcompletely match the vehicle-related information stored in thevehicle-related information storage 131. Even in such a case, if thedifference between the two is within a predetermined range, it may bedetermined that the authentication has succeeded, and if the differenceis not within the range, it may be determined that the authenticationhas failed.

The second processor 121 determines whether the authentication hassucceeded based on the result of the authentication process of step S135(step S140). When it is determined that the authentication has notsucceeded (step S140: NO), the process returns to step S110. On theother hand, when it is determined that the authentication has succeeded(step S140: YES), the second processor 121 determines whether the valueof the rolling counter is normal (step S145). The portable terminal 200increments a rolling counter by one each time a push switch (not shown)is pressed, and includes the value of the counter in the RF signal andtransmits the RF signal to the vehicle control apparatus 10. In thevehicle control apparatus 10, the second processor 121 also has arolling counter, and increments the counter value each time the RFsignal is received from the portable terminal 200. If there is nomalfunction in the RF communication between the portable terminal 200and the vehicle control apparatus 10, the value of the rolling counterincluded in the RF signal transmitted by the portable terminal 200 andthe value of the rolling counter included in the second processor 121should agree with each other. Therefore, in step S145, the secondprocessor 121 determines whether the rolling counter value included inthe received RF signal matches the value of the rolling counter includedin itself. If they match, it is determined that the rolling countervalue is normal. If they do not match, it is determined that the rollingcounter value is not normal. The case where the rolling counter valuesdo not match is assumed to be, for example, a case where a malfunctionoccurs in the configuration for transmitting the RF signal in theportable terminal 200.

When it is determined that the value of the rolling counter is notnormal (step S145: NO), the process returns to step S110 describedabove. On the other hand, when it is determined that the value of therolling counter is normal (step S145: YES), the second processor 121specifies the control content designated in the RF signal (step S150).The control content specified in the RF signal means the control contentinstructed to the vehicle control apparatus 10 by operating the pushswitch included in the portable terminal 200. For example, unlocking alldoors, opening rear seat doors, opening a back hatch, and so on.

The second processor 121 notifies that the user's operation has beenaccepted (step S155). Specifically, the second processor 121 notifiesthe user that the operation has been accepted by transmitting a commandto the body ECU 61 and performing a so-called answer-back operation inwhich the hazard lamp blinks. Instead of blinking the hazard lamp, or inaddition to blinking the hazard lamp, a predetermined sound may beoutput from a speaker or a horn to notify that the user's operation isaccepted.

The second processor 121 executes the control specified in step S150(step S160). For example, when unlocking the doors of the driver's seatis specified, a command is sent to the body ECU 61 to unlock all thedoors. After execution of step S160, the process returns to step S110described above.

The vehicle control apparatus 10 of the first embodiment described aboveis provided as follows. When it is determined that the RF signalreceived by the first process is not a regular wireless signal, thesecond process including the authentication of the portable terminal 200(step S135) is not executed. Here, the power consumption of the vehiclecontrol apparatus 10 when executing the first process is smaller thanthe power consumption of the vehicle control apparatus 10 when executingthe second process. The power consumption of the vehicle controlapparatus 10 can thus be suppressed as compared with each of (i) theconfiguration in which the second process is always executed instead ofthe first process and (ii) the configuration in which the first processand the second process are always executed. Therefore, even if power issupplied to the vehicle control apparatus 10 from the battery 70, it ispossible to prevent the battery exhaustion from occurring.

Further, the vehicle-related information included in the received RFsignal is compared with the vehicle-related information stored in thevehicle-related information storage 131. Then, when there is adifference outside a predetermined range, it is determined that theauthentication of the portable terminal 200 has failed. If there is nodifference outside the predetermined range, it is determined that theauthentication of the portable terminal 200 has succeeded. Therefore,the portable terminal 200 can be accurately authenticated.

Further, since the first processor 111 is configured by the ASIC 11 andthe second processor 121 is configured by the CPU 12, the powerconsumption of the first processor 111 can be reduced more easily thanthe power consumption of the second processor 121.

Further, the received RF signal is encoded by the bi-phase FSK systemwhich is a predetermined encoding process corresponding to themodulation process in the portable terminal 200. In addition, in theregular wireless signal determination process, the number of short bitssandwiched between two adjacent long bits in the received RF signal iscounted or determined. When the counted or determined number of shortbits between two adjacent long bits is an even number, the RF signal isdetermined to be a regular wireless signal. When an odd number, the RFsignal is not determined to be a regular wireless signal. Therefore, itis possible to accurately determine whether the received RF signal is aregular wireless signal, that is, whether the received wireless signalis a wireless signal transmitted from a portable terminal. The “portableterminal” here is not limited to the portable terminal 200, and meansany device having the same function as the portable terminal 200 andused as an electronic key for another vehicle.

Further, if YES is determined in all the determination processes ofsteps S205, S210, and S215, it is determined that the RF signal is aregular wireless signal. If NO is determined in at least one of thedetermination processes of steps S205, S210, and S215, it is determinedthat the RF signal is not a regular wireless signal. Therefore, it ispossible to accurately determine whether the received RF signal is aregular wireless signal.

If it is determined in step S205 that at least one of the time length ofthe short bit and the time length of the long bit is not within thepredetermined time range, it is determined that the received RF signalis not a regular wireless signal. Then, the regular wireless signaldetermination process ends. In this case, step S210 having a relativelylarge processing load is not executed. Therefore, the power consumptionby the ASIC 11 can be suppressed and the time required for the regularwireless signal determination process can be shortened as compared withthe configuration in which step S210 is always executed regardless ofthe time lengths of the short bit and the long bit.

Further, in the portable terminal 200 and the vehicle control apparatus10, the bi-phase FSK system is adopted as a modulation and encodingsystem in wireless communication in the RF band. Therefore, in step S210of the regular wireless signal determination process, it is possible toaccurately determine whether the received RF signal is a regularwireless signal.

B. Second Embodiment

The vehicle control apparatus 10 a according to a second embodimentshown in FIG. 6 is different from the vehicle control apparatus 10according to the first embodiment shown in FIG. 2 in that it includes afirst processor 130 instead of the first processor 111. Since the otherconfigurations of the vehicle control apparatus 10 a of the secondembodiment are the same as those of the vehicle control apparatus 10 ofthe first embodiment, the same elements are designated by the samereference signs, and detailed description thereof will be omitted. Thefirst processor 130 executes a first process. Similar to the firstprocess in the first embodiment, the first process is a process ofdetermining whether the received RF signal is a regular wireless signal.However, as will be described later, the steps of the first process ofthe second embodiment is slightly different from the steps of the firstprocess of the first embodiment.

In the second embodiment, the first processor 130 includes a firstdetermination unit 112 and a second determination unit 123. In thesecond embodiment, the ASIC 11 functions as the first determination unit112 instead of functioning as the first processor 111. The CPU 12 alsofunctions as a second determination unit 123 in addition to theabove-described second processor 121 and LF signal transmissioncontroller 122. The processing contents executed by the firstdetermination unit 112 and the second determination unit 123 will bedescribed later. In the second embodiment, the normal mode of the CPU 12includes a low speed mode and a high speed mode. The low speed mode isthe same as the high speed mode in that the CPU 12 can execute allexecutable functions. However, the low speed mode differs from the highspeed mode in that the CPU 12 operates at a lower frequency. In the lowspeed mode, the power consumption of the CPU 12 is smaller than that inthe high speed mode.

The RF signal reception handling process of the second embodiment shownin FIG. 7 is different from the RF signal reception handling process ofthe first embodiment shown in FIG. 3 in that step S125 a is executed inplace of step S125, and steps S127, S128 and S129 are additionallyexecuted. The other steps in the RF signal reception handling process ofthe second embodiment are the same as the RF signal reception handlingprocess of the first embodiment. Therefore, the same steps are denotedby the same reference signs, and detailed description thereof will beomitted. Note that in the second embodiment, the process of step S115 isreferred to as a “regular wireless signal first determination process”,although the process of step S115 in the second embodiment is the sameas the regular wireless signal determination process of step S115 in thefirst embodiment. This is for distinguishing from the regular wirelesssignal second determination process described later. The firstdetermination unit 112 executes this regular wireless signal firstdetermination process.

When it is determined in step S120 that the RF signal is a regularwireless signal (step S120: YES), the mode switching function unit (notshown) included in the CPU 12 switches the operation mode of the CPU 12from the sleep mode to the low speed mode (step S125 a).

After the operation mode of the CPU 12 is switched to the low speedmode, the second determination unit 123 executes the regular wirelesssignal second determination process (step S127). The regular wirelesssignal second determination process is a process of determining whetherthe received RF signal is a regular wireless signal, as in the regularwireless signal first determination process.

As shown in FIG. 8, in the regular wireless signal second determinationprocess, the second determination unit 123 determines whether the numberof short bits sandwiched by each pair of two long bits adjacent to eachother among all the pairs of two long bits adjacent to each other withina total of 300 bits is an even number (Step S310). Then, when it isdetermined that the number of short bits sandwiched by each pair of allthe pairs of two adjacent long bits within the total of 300 bits is aneven number (step S310: YES), the second determination unit 123determines that the received RF signal is a regular wireless signal(Step S315). On the other hand, when it is determined that the number ofshort bits sandwiched by any one pair of all the pairs of two adjacentlong bits within the total of 300 bits is not an even number (step S310:NO), the second determination unit 123 determines that the received RFsignal is not a regular wireless signal (step S320). As described above,the regular wireless signal second determination process is differentfrom step S210 of the regular wireless signal first determinationprocess only in that the amount of data as a determination target islarge. In step S210 in the regular wireless signal first determinationprocess (i.e., the regular wireless signal determination process), thedetermination target was all two long bits adjacent to each otherexisting within the range of 9 bits in total. In contrast, as describedabove, in the regular wireless signal second determination process, thedetermination target is all two long bits adjacent to each other thatare present in the range of 300 bits in total. It should be noted thatthe range of 300 bits in total may be replaced by a range of optionalbits larger than 9 bits. The range of 9 bits in total in step S210 maybe also referred to as a predetermined first bit width including apredetermined first number of bits, whereas the range of 300 bits intotal in step S310 may be also referred to as a predetermined second bitwidth including a predetermined second number of bits.

Since the data amount of determination target in step S210 is relativelysmall, the circuit scale of the first determination unit 112, that is,the ASIC 11 can be configured to be relatively small. On the other hand,since the data amount of determination target is relatively small, thedetermination accuracy is relatively low. On the other hand, the seconddetermination unit 123 (i.e., the CPU 12) can perform a process for alarge amount of data without significantly changing the configuration.Then, the determination accuracy can be made relatively high byperforming the determination on such a large data amount. As describedabove, in the second embodiment, it is possible to suppress the increasein the circuit scale of the ASIC 11 while improving the determinationaccuracy. Note that the power consumption of the CPU 12 when executingsteps S127 and S128 is smaller than the power consumption of the CPU 12when executing the second process including the authentication process(step S135).

As shown in FIG. 7, after execution of step S127, the seconddetermination unit 123 determines whether the received RF signal is aregular wireless signal based on the result of the regular wirelesssignal second determination process (Step S128). When it is determinedthat the signal is a regular wireless signal (step S128: YES), the modeswitching function unit (not shown) of the CPU 12 switches the operationmode of the CPU 12 from the low speed mode to the high speed mode (stepS129). After the operation mode of the CPU 12 is switched to the highspeed mode, the processing after step S130 described above, that is, thesecond process is executed. Therefore, in the second embodiment, thesecond process is executed in a situation where the operation mode ofthe CPU 12 is the high speed mode.

When it is determined in step S128 that the signal is not a regularwireless signal (step S128: NO), the process returns to step S110.Therefore, in this case, the second process is not executed. In thesecond embodiment, steps S115, S120, S127 and S128 correspond to a firstprocess in the present disclosure.

The vehicle control apparatus 10 a of the second embodiment describedabove has the same effects as the vehicle control apparatus 10 of thefirst embodiment. In addition, the vehicle control apparatus 10 a of thesecond embodiment performs (i) the determination process performed bythe ASIC 11 (i.e., the first determination unit 112) for each 9 bits intotal, and (ii) the determination process by the second determinationunit 123 by the CPU 12 in the low speed mode for every 300 bits intotal. Therefore, it is possible to perform the determination withhigher accuracy as compared with the configuration in which only thedetermination process is executed by the ASIC 11 every 9 bits in total.Further, the processing load of the ASIC 11 can be reduced, and thecircuit scale of the ASIC 11 can be suppressed from being extremelylarge, as compared with the configuration in which the determinationprocess is executed by the ASIC 11 every 300 bits in total.

C. Other Embodiments

(C1) In each of the embodiments, the portable terminal 200 is anelectronic key for the vehicle 100 that is carried by a user and used,but the present disclosure is not limited to this. For example, anydevice capable of wireless communication may be used as the portableterminal 200. Specifically, a portable phone device such as a so-calledsmartphone may be used as a portable terminal 200. In thisconfiguration, an application program for functioning as an electronickey for the vehicle 100 and an application for executing the process ofthe present disclosure are installed in advance in the portable phonedevice. The portable phone device may thus be operated as a portableterminal 200 by activating and executing these applications.

(C2) In each of the embodiments, in the authentication process (stepS135), the vehicle-related information included in the received RFsignal is compared with the vehicle-related information stored in thevehicle-related information storage 131. Then, if there is a differenceoutside a predetermined range, it is determined that the authenticationof the portable terminal 200 has failed. If there is no differenceoutside the predetermined range, it is determined that theauthentication of the portable terminal 200 has succeeded. However, thepresent disclosure is not limited to this. For example, a common secretkey may be set in advance for the portable terminal 200 and the vehiclecontrol apparatuses 10 and 10 a, and the portable terminal 200 mayencrypt the transmission data using the secret key. The vehicle controlapparatus 10 and 10 a may determine that the authentication issuccessful when the received data can be decrypted with the secret key,and may determine that the authentication is unsuccessful when thereceived data cannot be decrypted with the secret key.

(C3) In each of the embodiments, at least a part of the first process isexecuted by the ASIC 11, but instead of this, all of the first processmay be executed by the CPU 12. For example, in the first embodiment, theCPU 12 may be configured to function as a functional unit that executesthe first process, and the first process may be executed in the lowspeed mode. Further, in this configuration, a step of “switching theoperation mode of the CPU 12 from the sleep mode to the low speed mode”may be added between step S110 and step S115. Then, in step S125, theoperation mode of the CPU 12 is switched from the low speed mode to thehigh speed mode. Also in such a configuration, the power consumption ofthe vehicle control apparatus 10 when executing the first process can bemade smaller than the power consumption of the vehicle control apparatus10 when executing the second process.

(C4) In the second embodiment, the operation mode of the CPU 12 whenexecuting steps S127 and S128 is the low speed mode, but may be the highspeed mode. In such a configuration, in step S125 a, the operation modeof the CPU 12 may be switched from the sleep mode to the high speedmode, and step S129 may be omitted. Even in such a configuration, whenthe received RF signal is not a regular wireless signal, the operationmode of the CPU 12 remains in the sleep mode, and the regular wirelesssignal second determination process is not executed. The powerconsumption can thus be suppressed.

(C5) The regular wireless signal determination process of the firstembodiment and the regular wireless signal first determination processof the second embodiment include three determination processes of stepsS205, S210, and S215. However, the present disclosure is not limitedthereto. Of these three determination processes, any combinationincluding step S210 may be used. Further, the order of these threedetermination processes may be exchanged. In addition, in eachembodiment, another process may be added to the first process andexecuted.

(C6) In each of the embodiments, at least one step in the second process(steps S130 to S160) may be omitted or replaced with another step. Forexample, in step S155, the notification that the user operation isreceived may be omitted. Alternatively, the history of the useroperation may be stored in the memory 13 instead of executing thenotification that the user operation is received. Further, for example,a parity check of the received data may be added and executed. In such aconfiguration, the portable terminal 200 adds a parity bit for eachpredetermined bit width and transmits the RF signal.

(C7) In each of the embodiments, the portable terminal 200 and thevehicle control apparatus 10 adopt the bi-phase FSK system as amodulation and encoding process in wireless communication in the RFband. However, the present disclosure is not limited thereto. Anotherconfiguration may be provided to adopt an optional encoding process inwhich two consecutive short bits represent 0 and one long bit represents1 and an optional modulation process corresponding to such an encodingprocess. For example, CMI (Code Mark Inversion code) may be adopted asan encoding process.

(C8) In the above-described embodiment, a part of the configurationimplemented by hardware or hardware circuitry may be replaced withsoftware, and conversely, a part of the configuration implemented bysoftware may be replaced with hardware or hardware circuitry. Forexample, the LF signal transmission controller may be realized by anintegrated circuit, a discrete circuit, or a module combining thesecircuits. Further, when partial or all of the functions in the presentdisclosure is implemented by software, the software, that is, thecomputer program can be provided as the computer program itself or canbe provided as a computer-readable non-transitory storage medium thatstores the computer program. The computer-readable non-transitorystorage medium is not limited to a portable storage medium, such as aflexible disk or a CD-ROM, but also includes an internal storage device,such as RAM or ROM included in the computer. The computer-readablenon-transitory storage medium also includes a hard disk which isconnected to the computer as an external storage device. That is, thecomputer-readable non-transitory storage medium has a broad meaningincluding any storage medium in which data can be stored in fixed mannerbut not temporarily.

The present disclosure should not be limited to the embodimentsdescribed above, and various other embodiments may be implementedwithout departing from the scope of the present disclosure. For example,the technical features in each embodiment may be used to solve some orall of the above-described issues or to provide one of theabove-described effects. In order to achieve a part or all, replacementor combination can be appropriately performed. Also, some of thetechnical features may be omitted as appropriate.

For reference to further explain features of the present disclosure, thedescription is added as follows.

Vehicle control apparatuses mounted on vehicles may include a vehiclecontrol apparatus that wirelessly communicates with a portable terminalcarried by a user of the vehicle to realize a smart entry function or aremote keyless entry function. The smart entry function means a functionof unlocking the door of the vehicle when the portable terminal enters awireless communication area near the vehicle. Further, the remotekeyless entry means a function of locking or unlocking the door of thevehicle according to the operation of the push switch of the portableterminal. Generally, such a vehicle control apparatus, which may also becalled an in-vehicle apparatus, can receive a signal in an RF band (forexample, 300 MHz to 400 MHz) transmitted from a portable terminal, andcan transmit a signal in an LF band (for example, 30 kHz to 300 kHz) tothe portable terminal. The vehicle control apparatus is configured as acomputer including a CPU, a ROM, and a RAM. Upon receiving a signal inthe RF band from a portable terminal, the vehicle control apparatus mayauthenticate whether the portable terminal of a transmission source isan authorized portable terminal carried by the user of the vehicle basedon the information such as the ID indicated by the signal.

Vehicles may be parked in various places. Therefore, the vehicle controlapparatus may receive various external noises, that is, signals in theRF band output from a device different from a regular portable terminal.Such an external noise may include a signal transmitted from a portableterminal for another vehicle control apparatus, a signal of wirelesscommunication between a management apparatus and a device installed ineach parking space in the parking lot, or wireless waves output fromvarious radio towers. It is useless to perform the above-mentionedauthentication against such external noise. The power consumption of theCPU that executes such authentication increases. This results in anissue posing a so-called “battery exhaustion” in which the charge amountof the battery that supplies power to the vehicle control apparatus isreduced and the battery cannot supply the power. It is thus desired toprovide a vehicle control apparatus capable of accurately determiningwhether a received wireless signal is a wireless signal transmitted froma portable terminal.

An aspect of the present disclosure described herein is set forth in thefollowing clauses.

According to an aspect of the present disclosure, a vehicle controlapparatus is mounted on a vehicle to perform wireless communication witha portable terminal carried by a user of the vehicle, and control atleast a part of functions of the vehicle according to an instructionfrom the portable terminal. The vehicle control apparatus includes afirst processor configured to execute a first process including adetermination process that determines whether or not a received signal,which is a wireless signal received by an antenna mounted on the vehicleand encoded, is a regular wireless signal transmitted from the portableterminal. Herein, the portable terminal outputs the wireless signal bymodulating a transmission data with a modulation corresponding to apredetermined encoding process in which two consecutive short bitsrepresent 0 and one long bit represents 1. The received signal isencoded with the encoding process in a signal receiver mounted on thevehicle. The determination process includes a first sub determinationprocess. The first sub determination process is configured to (i)determine that the received signal is the regular wireless signal inresponse to a counted number of short bits sandwiched by two long bitsadjacent to each other in the received signal being an even number, and(ii) determine that the received signal is not the regular wirelesssignal in response to the counted number of short bits sandwiched by twolong bits adjacent to each other in the received signal being an oddnumber.

According to the vehicle control apparatus of the above aspect, thereceived signal is encoded by a predetermined encoding processcorresponding to the modulation process in the portable terminal. Inaddition, the determination process includes a first sub determinationprocess. The first sub determination process determines that thereceived signal is a regular wireless signal when a counted number ofshort bits sandwiched by two adjacent long bits in the received signalis even, and determine that the received signal is not a regularwireless signal when the counted number of short bits sandwiched by twoadjacent long bits in the received signal is odd. Therefore, it ispossible to accurately determine whether or not the received signal is aregular wireless signal, that is, whether or not the received wirelesssignal is a wireless signal transmitted from a portable terminal.

The present disclosure can be realized, in addition to the vehiclecontrol apparatus, in various forms such as: a vehicle equipped with avehicle control apparatus; a vehicle electronic key system; a portableterminal authentication apparatus; a vehicle control method; a portableterminal authentication method; a computer program for realizing theseapparatuses/systems and methods; a storage medium storing such computerprogram.

What is claimed is:
 1. A vehicle control apparatus mounted on a vehicleto perform wireless communication with a portable terminal carried by auser of the vehicle, and control at least a part of functions of thevehicle according to an instruction from the portable terminal, thevehicle control apparatus comprising: a first processor configured toexecute a first process including a determination process thatdetermines whether or not a received signal, which is a wireless signalreceived by an antenna mounted on the vehicle and encoded, is a regularwireless signal transmitted from the portable terminal, wherein: theportable terminal outputs the wireless signal by modulating atransmission data with a modulation corresponding to a predeterminedencoding process in which two consecutive short bits represent 0 and onelong bit represents 1; the received signal is encoded with the encodingprocess in a signal receiver mounted on the vehicle; the determinationprocess includes a first sub determination process, the first subdetermination process being configured to determine that the receivedsignal is the regular wireless signal in response to a counted number ofshort bits sandwiched by two long bits adjacent to each other in thereceived signal being an even number, and determine that the receivedsignal is not the regular wireless signal in response to the countednumber of short bits sandwiched by two long bits adjacent to each otherin the received signal being an odd number.
 2. The vehicle controlapparatus according to claim 1, wherein: in the regular wireless signal,a predetermined determination bit that includes one or more bits is setfor each predetermined first bit width including a predetermined firstnumber of bits; the determination process includes two or more subdetermination processes that include (i) the first sub determinationprocess and (ii) at least one sub determination process among a secondsub determination process and a third sub determination process; thesecond sub determination process being configured to determines whetheror not a time length of at least one of the short bit and the long bitincluded in the received signal is within a predetermined time range,determines that the received signal is the regular wireless signal inresponse to determining that the time length is within the time range,and determines that the received signal is not the regular wirelesssignal in response to determining that the time length is not within thetime range, the third sub determination process being configured tospecify whether, in the received signal, the set determination bit ispresent within a predetermined second bit width including apredetermined second number of bits equal to or larger than the firstnumber of bits included in the first bit width, determine that thereceived signal is the regular wireless signal in response to specifyingthat the set determination bit is present, and determine that thereceived signal is not the regular wireless signal in response tospecifying that the set determination bit is not present; and the firstprocessor is configured to determine that the received signal is theregular wireless signal in response to each sub determination processamong the two or more sub determination processes determining that thereceived signal is the regular wireless signal, and determine that thereceived signal is not the regular wireless signal in response to atleast one sub determination process among the two or more subdetermination processes determining that the received signal is not theregular wireless signal.
 3. The vehicle control apparatus according toclaim 2, wherein: the determination process includes at least the firstsub determination process and the second sub determination process; thefirst processor is configured to end the determination process withoutexecuting the first sub determination process in response to the secondsub determination process determining that the received signal is notthe regular wireless signal, and execute the first sub determinationprocess in response to the second sub determination process determiningthat the received signal is the regular wireless signal.
 4. The vehiclecontrol apparatus according to claim 1, wherein: the predeterminedencoding process is bi-phase FSK (Frequency Shift Keying).